The inventive concepts relate to image sensors. More particularly, the inventive concepts relate to image sensors capable of improving charge transfer efficiency.
Image sensors may convert an optical image into an electrical signal. As computer and communication industries have developed, demand for high performance image sensors has increased for various applications, such as digital cameras, camcorders, personal communication systems (PCS), gaming devices, security cameras, and medical micro-cameras.
Image sensors may include charge coupled devices (CCDs) and complementary metal-oxide-semiconductor (CMOS) image sensors. Driving CMOS image sensors may be relatively simple and CMOS image sensors may include image sensing elements and a signal processing circuit that are integrated on a single chip. Thus, CMOS image sensors can be reduced in size relatively easily. In addition, CMOS image sensors may have low power consumption, so they may be well-suited for devices having limited battery capacity. CMOS image sensors may also be manufactured using a CMOS process technique to reduce their manufacturing costs. For at least these reasons, CMOS image sensors have been increasingly used in various fields.